JPH05224334A - Silver halide photographic emulsion - Google Patents

Abstract

PURPOSE:To improve such photographic characteristics as sensitivity and illuminance failure characteristics. CONSTITUTION:This silver halide photographic emulsion contains silver iodobromide or silver bromide particles contg. two or more kinds of multivalent metal compds. At least one of the metal compds. is uniformly distributed in the particles and at least one of the other metal compds. is locally distributed in the particles and/or on the surfaces of the particles. The metal compds. are preferably compds. of Tl, Pb, Fe, Ru, Ir, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silver halide photographic emulsion, and more particularly to a silver halide photographic emulsion having improved photographic characteristics such as sensitivity and illuminance failure characteristic due to metal doping.

[0002]

BACKGROUND OF THE INVENTION In recent years, there has been an increasing demand for higher sensitivity and higher image quality of silver halide photographic light-sensitive materials. In order to meet such demands, in order to improve the light-sensitive properties of silver halide emulsions, a technique for controlling the charge carriers (carriers) in the silver halide grains involved in the light-sensitive process is required.

It is considered that four carriers mainly involved in the photosensitization process are interstitial silver ions and silver ion vacancies which are Frenkel defect pairs, electrons and holes generated by light irradiation. In emulsions containing dyes, electrons and holes are generated in the dye, both of which can be injected into the silver halide grains. In order to achieve the ideal improvement of the photosensitive characteristics of silver halide grains, total control design of these carriers,
That is, it is necessary to combine the independent control of each carrier.

The carrier can be controlled by providing a halide composition difference in the silver halide grains. For example, internal high-iodine type silver iodobromide core-shell grains having a high AgI content layer inside the grains are often used particularly in color films and the like, and are known to have a higher photosensitive quantum yield than grains of uniform composition. ing. Regarding the sensitizing mechanism of the internal high iodine grains, JP-A-60-1433
No. 31 describes the possibility of charge separation of holes and electrons due to bending of the band structure due to the difference in halide composition.

Also, Nakayama et al. Have proposed a charge separation model of electrons and dye holes by a shallow electron trap due to the high iodine phase (Abstracts of the Annual Meeting of the Photographic Society of Japan in 1987, p. 49). On page 246 of "Basic Silver Salt Photography" (Corona Publishing Co.) edited by the Photographic Society of Japan, it is shown that in a silver iodobromide emulsion, lattice defects, that is, interstitial silver ions and silver ion vacancies are increased by iodine ions. Has been done.

[0006] As described above, the carriers can be controlled by the difference in the halide composition in the particles, but it is insufficient in that the carriers cannot be controlled independently. Further, the halide composition of the particles is concerned not only with the photosensitivity but also with the uniformity of the particle growth, chemical sensitization and development properties, and it is not always possible to achieve ideal carrier control within the range that does not impair those properties. Absent.

Particularly in the case of silver iodobromide emulsion, the mixed crystal ratio is limited, unlike silver chlorobromide which forms mixed crystals at an arbitrary ratio.
Therefore, as compared with silver chlorobromide, the carrier control range is limited due to the difference in halide composition. In addition, as the silver iodide content in the silver iodobromide emulsion increases, the composition between grains
It is known that the size distribution is widened (The Photographic Society of Japan, Fundamentals of Photographic Engineering, Silver Salt Photography, Corona Publishing Co., Ltd. 246
page). As another effective means for controlling carriers, metal doping is known.

Metal doping is a technique for improving photographic characteristics by mainly incorporating a polyvalent metal compound in silver halide grains. JP-A-62-70
No. 42, JP-A-1-105940 and the like, a technique for doping an Ir compound, and JP-A No. 63-183438 and JP-A No. 1-245242, for example, a technique for doping an Rh compound, JP-A-1-121844. Discloses techniques for doping Fe compounds. The technique for doping such a single metal compound is well known, and research has been conducted on various metals. However, doping of a single compound is not sufficient for ideal carrier control.

JP-A-63-184740, JP-A-2-
No. 125245 discloses a technique for doping two kinds of metal compounds. In addition, JP-A-62-260137
Japanese Patent Laid-Open No. 2-156239 describes doping one or more kinds of metal compounds as one aspect of the invention. However, simply doping two or more kinds of metal compounds is not sufficient. For ideal carrier control, it seems necessary to have a concentration distribution that suits the function of each dopant.

Japanese Unexamined Patent Publication (Kokai) No. 1-183647 discloses a technique for improving the photosensitivity by allowing a localized silver bromide phase and iron ions to exist in silver chlorobromide emulsion grains. An example is shown in which is doped with different distribution states. However, this technique utilizes a difference in halide composition such as a localized phase of silver bromide, and cannot be applied to a silver iodobromide emulsion which is limited in control due to the difference in halide composition.

Japanese Unexamined Patent Publication No. 59-216136 is a patent relating to a direct positive light-sensitive material and discloses a technique of doping two kinds of metal ions in different processes. However, one of the metal ions is used for core formation for directly obtaining a positive image, and is not a technique for controlling carriers by a plurality of dopants.

As described above, for the purpose of improving the characteristics of silver iodobromide or silver bromide emulsion, two or more kinds of metal compounds are doped in optimal and different distributions in order to perform ideal carrier control. No invention has been made.

[0013]

It is an object of the present invention to improve the photographic characteristics of silver halide emulsion grains such that sensitivity and illuminance failure characteristics are improved by performing optimum carrier control only by metal doping independently of the halide composition distribution. To provide a silver halide photographic emulsion.

[0014]

The above object of the present invention is to provide a silver halide photographic emulsion comprising silver halide grains containing two or more polyvalent metal compounds, wherein at least one of the metal compounds is evenly distributed in the grains. And at least one of the other metal compounds is locally distributed inside the grain and / or on the surface of the grain.

The structure of the present invention will be described in detail below. The silver halide photographic emulsion of the present invention comprises silver iodobromide grains or silver bromide grains. Although it can be applied to any composition distribution of silver iodobromide, grains having a small difference in halide composition in order to utilize the uniformity of emulsion characteristics such as grain size distribution, crystal habit, chemical sensitization, and developability. It is preferable to combine with. In the case of silver iodobromide, the difference between the phase having the highest iodide content and the phase having the lowest iodide content is preferably 10 or less in mol%. Further, 5 or less is more preferable, and most preferable is a grain having a uniform iodide content within the grain. Pure silver bromide is preferred as well as grains having a uniform iodide content.

The term "doping" or "doping" refers to the inclusion of substances other than silver or halide ions in the silver halide grains. The term "dopant" refers to compounds that dope silver halide grains.

The dopants are Mg, Al, Ca, Sc,
Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Z
n, Ga, Ge, Sr, Y, Zr, Nb, Mo, Tc,
Ru, Rh, Pd, CdSn, Ba, Ce, Eu, W,
Metal compounds such as Re, Os, Ir, Pt, Hg, Tl, Pb and Bi can be preferably used. These metals may be two or more different metals, and the portions other than the metal of the compound may be the same or different, and the same metal may form two or more different compounds.

The metal compound to be doped is preferably selected from a single salt or a metal complex. When selected from a metal complex, a hexacoordinate, a pentacoordinate, a tetracoordinate, and a bicoordinate complex are preferable, and an octahedral hexacoordinate and a plane tetracoordinate complex are more preferable. The complex may be a mononuclear complex or a polynuclear complex. Further, as the ligands forming the complex, CN ⁻ , C
O, NO ₂ ^-, 1,10-phenanthroline, 2,2 '
- bipyridine, SO ₃ ^-, ethylenediamine, NH _{3,
Pyridine, H 2 O, NCS, NCO} , NO 3 -, SO 4
_{^{2-, OH -, CO 3 2-}} , SSO 3 2-, N 3 -, S ^2- ,
F ⁻ , Cl ⁻ , Br ⁻ , I ^{− and the} like can be used.

As a metal complex, K ₄ Fe (CN) ₆ , K
₃ Fe (CN) ₆ , K ₂ IrCl ₆ , K ₂ IrBr ₆ ,
K ₂ ReCl ₆ , K ₂ RuCl ₆ , K ₂ Ru (C
Particularly preferred are potassium salts such as N) ₆ and K ₂ Os (CN) ₆ or ammonium salts, sodium salts and cesium salts of these complexes.

As the single salt, halides, nitrates, sulfates and perchlorates of the above metals are preferably used. FeCl ₂ , FeCl ₃ , Pb (NO ₃ ) ₂ , Ir
Fe ²⁺ , Fe ³⁺ , Pb ²⁺ , Ir ³⁺ , Ir such as Cl ₃
⁴⁺ halides and nitrates are particularly preferably used.

One type of dopant does not always have controllability for one carrier. Most of the polyvalent metal ions are thought to affect interstitial silver ions, and at the same time, some of the polyvalent metal ions are considered to have hole trapping properties or electron trapping properties.

However, the dopants can be classified into three types, that is, the electron trapping property, the hole trapping property, and the interstitial silver ion controlling type according to the main characteristics. For example, it has been reported by Leubner that an Ir complex has an electron trapping property as a main property in a doped state (The Journal of Photograph).
pic Science Vol. 31, 93 (19
83). Further, for example, a technique of using divalent iron ions as a hole trap is disclosed in JP-A-1-121844.

The dopant for localized distribution is preferably a trap-providing dopant that controls electrons and / or holes. The dopant that is uniformly distributed is preferably a dopant that controls the Frenkel defect pair of interstitial silver ions and silver ion vacancies, or a dopant that imparts a hole trap.

In the present invention, “uniformly distributed” means that the concentration ratio between the highest concentration portion and the lowest concentration portion of the dopant exists at a rate of ½ or more over 80% or more of the grain volume. The uniformly distributed dopant is preferably present in 85% or more of the particle volume, more preferably 90% or more. Most preferred is when present over 100% of the particle volume. The ratio of the minimum concentration to the maximum concentration of the uniformly distributed dopant is preferably two thirds or more, more preferably three quarters or more. The uniformly distributed dopant is preferably contained at a concentration of 10 ⁻⁹ to 10 ⁻³ mol, and more preferably 5 × 10 ⁻⁵ to 10 ⁻⁷ mol, per mol of the total silver amount.

In the present invention, the term “locally distributed” or “localized distribution” means that the particles are distributed over 50% or less of the particle volume. The preferred distribution pattern of the localized distribution dopant depends on the type of metal ion. This is because the ability to trap electrons or holes differs depending on the type of metal ion. For example, Ir is preferably present at a concentration of 10 ⁻⁵ to 10 ⁻⁸ mol per mol of total silver. The distribution range is preferably over 10% or less of the particle volume. For example, Fe is preferably present in a concentration of 10 ⁻³ to 10 ⁻⁷ mol per mol of total silver. The distribution range is 45 of the particle volume.
% To 15% is preferred.

A monodisperse silver halide emulsion is preferably used for the silver halide photographic emulsion of the present invention. The monodisperse silver halide emulsion means an emulsion in which the weight of silver halide contained in the grain size range of ± 20% around the average grain size d is 70% or more of the total weight of silver halide, and preferably 80
% Or more, more preferably 90% or more.

The monodisperse emulsion has a width of distribution of 20% or less, more preferably 15%, which is defined by 100 times the value obtained by dividing the standard deviation of the grain size by the average grain size.
It is as follows. The particle size in the present invention means the side length of a cube having the same volume as the particles. The average grain size of the silver halide emulsion of the present invention is preferably 0.1 to 10 μm, more preferably 0.1 to 5.0 μm.
More preferably, it is 0.3 to 1.4 μm.

The silver halide emulsion of the present invention is a cube, 1
It may be a normal crystal such as a tetrahedron or an octahedron, or a twin crystal such as a flat plate. Also, a mixture of these may be used. In the case of a flat twin, the ratio of the equivalent circle diameter of the projected area of the grain to the grain thickness of 1 to 20 is preferably 60% or more of the projected area, and further 1.2 or more,
It is preferably less than 8.0, particularly preferably 1.5 or more and less than 5.0.

Monodisperse normal crystal emulsions are described in, for example, Japanese Patent Laid-Open No.
9-177535, 60-138538, 59
-52238, 60-143331, 60-3
5726, 60-258536 and 61-14
It can be produced by referring to the method disclosed in Japanese Patent No. 636 or the like.

Monodisperse twinned emulsions are described in, for example, JP-A-61 / 1986.
It can be obtained by referring to the method of growing a spherical seed emulsion disclosed in JP-A-14636. For the growth of the silver halide emulsion of the present invention, Japanese Patent Laid-Open No.
The apparatus shown in 2-160128 is preferably used.

For growth, it is preferable to add a silver nitrate aqueous solution and a halide aqueous solution by the double jet method. The iodide can also be supplied to the system as silver iodide. The addition rate is such that new nuclei are not generated, and there is no spread of the size distribution due to Ostwald ripening, that is, 30 to 100 times the speed at which new nuclei are generated.
It is preferable to add in the range of%.

As another condition for enlarging the grains, a method of enlarging the grains by adding fine silver halide grains and recrystallizing the grains can be mentioned as shown on page 88 of the Annual Meeting of the Photographic Society of Japan, 1983. .. The growth conditions for the silver halide emulsion are as follows: pAg 5-11, temperature 40-85.
C. and pH 1.5-12 are preferred.

The following method is preferably used as a method of adding a dopant suitable for obtaining the silver halide emulsion of the present invention. (1) At the time of grain production, a dopant is added to the mother liquor before the addition of an aqueous silver nitrate solution or the like is started. (2) At the time of grain production, a dopant is previously added to an additive solution such as an aqueous silver nitrate solution, an aqueous halide solution or a fine grain emulsion. (3) Dissolving the dopant in a suitable solvent during particle production,
Alternatively, it is added in a state of being dispersed in an appropriate dispersion medium.

The method (2) is particularly preferable for uniform distribution of the dopant. In order to locally distribute the dopant, any of the methods (1), (2) and (3) may be used depending on the case.
It can be preferably applied.

The silver halide photographic emulsion of the present invention is preferably desalted by a known method after the formation of the silver halide grains in the finished emulsion which has been provided with the predetermined grain conditions. As the desalting method, for example, an agglomerated gelatin agent or the like may be used, or a Nudel water washing method performed by gelatinizing gelatin may be used, and inorganic salts composed of a polyvalent anion, such as sodium sulfate and anions. Coagulation method using organic surfactants and anionic polymers (eg polystyrene sulfonic acid), and precipitation method (flocculation method) using gelatin derivatives (eg acylated gelatin, carbamoylated gelatin) Good.

The silver halide grains desalted in this manner are redispersed in a gelatin solution to prepare a silver halide emulsion. The silver halide photographic emulsion of the present invention can be preferably used in a silver halide color photographic light-sensitive material.

When a color photographic light-sensitive material is constructed using the silver halide photographic emulsion of the present invention, the silver halide photographic emulsion used is one which has been physically ripened, chemically ripened and spectrally sensitized. Additives used in such processes are described in Research. Disclosure No. 17643, No.
18716 and No. 308119 (R respectively
D17463, RD18716 and RD308119). The following shows the locations.

Item RD308119 RD17643 RD18716 Page / Item page Page Chemical sensitizer 996 III-A Item 23 648 Spectral sensitizer 996 IV-A-A, B, 23-24 648-9 C, D, H , I, J item Supersensitizer 996 IV-AE, J item 23-24 648-9 Antifoggant 998 VI 24-25 649 Stabilizer 998 VI 24-25 649

Known photographic additives that can be used in the construction of a color photographic light-sensitive material using the silver halide photographic emulsion of the present invention are also described in the above Research Disclosure. The relevant parts are shown in the table below.

Item RD308119 RD17643 RD18716 page / page page color turbidity inhibitor 1002 VII-I 25 650 Dye image stabilizer 1001 VII-J 25 Whitening agent 998 V 24 UV absorber 1003 VIII-C, 25-26 XIIIC paragraph light absorber 1003 VIII 25-26 light-scattering agent 1003 VIII filter dye 1003 VIII 25-26 binder 1003 IX 26 651 antistatic 1006 XIII 27 650 hardener 1004 X 26 651 plastic X-ray II 1006 650 moisturizing agent 1006 XII 27 650 activator / coating aid 1005 XI 26-27 650 agent matting agent 1007 XVI image agent 1011 XXB item (included in photosensitive material)

Various couplers can be used in constructing a color photographic light-sensitive material using the silver halide photographic emulsion of the present invention, and specific examples thereof are described in the above-mentioned Research Disclosure. The following shows the relevant locations.

The page-item RD17643 items RD308119 th page yellow coupler 1001 VII-D section VII C~G term magenta coupler 1001 VII-D section VII C~G Cyan coupler 1001 VII-D section VII C~G Colored Coupler 1002 VII-G term VII G term DIR coupler 1001 VII-F term VII F term BAR coupler 1002 VII-F term Other useful residues Release coupler 1001 VII-F term Alkali-soluble cap 1001 VII-E term

Additives used in the construction of a color photographic light-sensitive material using the silver halide photographic emulsion of the present invention are R
It can be added by the dispersion method described in D308119XIV.

When a color photographic light-sensitive material is constituted by using the silver halide photographic emulsion of the present invention, the above-mentioned RD1764 is used.
3 page 28, RD18716 pages 647-8 and RD3.
The supports described in XVII of 08119 can be used. The color photographic light-sensitive material using the silver halide photographic emulsion of the present invention may be provided with auxiliary layers such as a filter layer and an intermediate layer described in the above-mentioned item XVII-K of RD308119. The color photographic light-sensitive material using the silver halide photographic emulsion of the present invention is the RD described above.
Various layer configurations such as the forward layer, the reverse layer, and the unit configuration described in 308119VII-K can be adopted.

The silver halide photographic emulsion of the present invention is a color negative film for general use or movies, a color reversal film for slides or televisions, color paper,
It can be preferably applied to various color light-sensitive materials represented by color positive films and color reversal papers. The color photographic light-sensitive material using the silver halide photographic emulsion of the present invention is described in the above-mentioned RD17643, pages 28-29,
RD18716, page 615 and RD308119, XI
The development processing can be carried out by the usual method described in the item X.

[0046]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

Example [Preparation of Comparative Emulsion Em-1] While keeping the liquid A at 40 ° C.,
The solution B and the C ₁ and C ₂ solutions were added by the double jet method at the addition rates shown in Table 1 with sufficient stirring. At that time, pH and pAg were controlled as shown in Table 1 using the liquids D and E. The emulsion obtained by washing and dispersing the obtained emulsion with water was designated as Em-1. As a result of electron microscopic observation, the particles were regular octahedral particles having an average particle size of 1.00 μm.

[Preparation of Comparative Emulsion Em-2] 9 in C ₁ Solution
An emulsion obtained in the same manner as Em-1 except that 187.0 mg of lead nitrate was added to each of 3.7 mg and C ₂ solution was Em.
-2.

[Preparation of Comparative Emulsion Em-3] _{1 for} C ₁ Solution
An emulsion obtained in the same manner as Em-1 except that 29.8 mg of potassium ferrocyanide trihydrate was added to 5.0 mg of C ₂ solution was designated as Em-3.

[Preparation of Comparative Emulsion Em-4] C- ₁ Solution 15
1.2 mg, except that 301.8 mg of potassium hexachlorothalium (III) was added to the C ₂ solution, respectively.
The emulsion obtained in the same manner as Em-1 was designated as Em-4.

[Preparation of Comparative Emulsion Em-5] _{1 for} C ₁ Solution
An emulsion obtained in the same manner as Em-1 except that 33.0 mg of potassium hexacyanoruthenium (II) trihydrate was added to 6.6 mg of C ₂ solution was designated as Em-5.

[Preparation of Comparative Emulsion Em-6] 4 in C ₁ Solution
An emulsion prepared in the same manner as Em-1 except that 4.8 mg of potassium ferrocyanide trihydrate was added, respectively.
It was set to -6.

[Preparation of Comparative Emulsion Em-7] Solution B remains 4
When the volume reached 40.6 ml, the addition was stopped,
An emulsion obtained in the same manner as Em-1 except that 1.06 ml of 2.0 × 10 ⁻³ M potassium hexachloroiridium (IV) aqueous solution was added and the addition was restarted was designated Em-7. .. However, the potassium hexachloroiridium (IV) aqueous solution was used immediately after preparation.

[Preparation of Comparative Emulsion Em-8] Solution B remains 4
Discontinue the addition when 4.8 ml is reached and 2 ×
An emulsion obtained in the same manner as Em-1 except that the addition of 1.06 ml of a 10 ^-3 M potassium hexachlororuthenium (IV) aqueous solution was restarted 5 minutes after the addition was performed.
It was set to -8. However, the potassium hexachloroiridium (IV) aqueous solution was used immediately after preparation.

[Preparation of comparative emulsion Em-9] 28 in C ₂ solution
An emulsion obtained in the same manner as Em-7, except that 0.7 mg of lead nitrate was added, was designated as Em-9.

[Preparation of Comparative Emulsion Em-10] 4 in C ₁ Solution
An emulsion obtained in the same manner as Em-7, except that 4.8 mg of potassium ferrocyanide trihydrate was added, was designated as Em-10.

[Preparation of Comparative Emulsion Em-11] 9 to C ₁ Solution
3.7 mg lead nitrate, 15.0 mg potassium ferrocyanide, 187.0 mg lead nitrate and 29.8 m in C ₂ solution
except that g of potassium ferrocyanide was added,
An emulsion obtained in the same manner as Em-1 was designated as Em-11.

[Preparation of Emulsion Em-12 of the Present Invention] Except that 93.7 mg of lead nitrate and 44.8 mg of potassium ferrocyanide were added to the C ₁ solution, and 187.0 mg of lead nitrate was added to the C ₂ solution, respectively. The emulsion obtained in the same manner as Em-1 was designated as Em-12.

[Preparation of Emulsion Em-13 of the Present Invention] Emulsion obtained in the same manner as Em-7 except that 93.7 mg of lead nitrate was added to the C ₁ solution and 187.0 mg of lead nitrate was added to the C ₂ solution, respectively.
m-13.

[0061] except that [the present invention Emulsion Em-14 Preparation of] 151.2mg to C ₁ solution, C ₂ solution of hexachloro thallium (III) acid potassium 301.8mg were added respectively, in the same manner as Em-7 The obtained emulsion was designated as Em-14.

[0062] [invention Emulsion Em-15 Preparation of] 15.0mg to C ₁ solution, except that each added potassium ferrocyanide 29.8mg to C ₂ solution, the emulsion obtained in the same manner as Em-7 Em It was set to -15.

[Preparation of Emulsion Em-16 of the Present Invention] Emulsion obtained in the same manner as in Em-8 except that 93.7 mg of lead nitrate was added to the C ₁ solution and 187.0 mg of lead nitrate was added to the C ₂ solution, respectively.
m-16.

[0064] except that [the present invention Emulsion Em-17 Preparation of] 15.0mg to C ₁ solution, C ₂ solution of potassium ferrocyanide trihydrate 29.8mg was added respectively, in the same manner as Em-8 obtained The resulting emulsion was designated as Em-17.

[0065] except that [the present invention Emulsion Em-18 Preparation of] 16.6mg to C ₁ solution, C ₂ solution of hexacyano ruthenium (II) potassium trihydrate 33.0mg was added respectively, Em-8 The emulsion obtained in the same manner as above was designated as Em-18.

[0066] 93.7mg [present invention Emulsion Em-19 Preparation of] 16.6mg to C ₁ solution, the hexacyano ruthenium (II) potassium trihydrate 33.0mg to C ₂ solution, and the C ₁ solution , An emulsion obtained in the same manner as in Em-8 except that 187.0 mg of lead nitrate was added to the C ₂ solution.
It was set to m-19.

[Preparation of Emulsion Em-20 of the Present Invention] Except that 93.7 mg of lead nitrate and 44.8 mg of potassium ferrocyanide were added to the C ₁ solution, and 187.0 mg of lead nitrate was added to the C ₂ solution, respectively. An emulsion obtained in the same manner as Em-7 was designated as Em-20.

As a result of observation with an electron microscope, the emulsion grains of Em-2 to 20 had almost the same grain size and crystal habit as Em-1.

Solution A Ocein gelatin 101.7 g Polyisopropylene-polyoxyethyleneoxy-succinic acid ester sodium salt (10% methanol solution) 30.0 ml Acetic acid (56%) 93.3 ml Ammonia (28%) 155.4 ml Silver bromide seed emulsion (average grain size 0.240 μ) Equivalent to 0.1465 mol Pure water 10593.0 ml

Liquid B Silver nitrate 1775.1 g Ammonia (28%) 1448.0 ml Pure water 4975.5 ml

Solution C ₁ Ossein gelatin 33.2 g Potassium bromide 406.8 g Potassium iodide 11.58 g Pure water 1660.8 ml

Liquid C ₂ Ossein gelatin 66.3 g Potassium bromide 811.9 g Potassium iodide 23.11 g Pure water 3314.7 ml

Liquid D Acetic acid (56%) 3000.0 ml Liquid E Potassium bromide 208.0 g Pure water 500.0 ml

[0074]

[Table 1]

[Evaluation of Sensitivity] The emulsions of Em-1 to 7 were optimally chemically sensitized with hypo, and then 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene, polyvinylpyrrolidone, coating were applied. Dioctyl sodium sulfosuccinate as an auxiliary agent and 1,2-bis (vinylsulfonyl) ethane as a hardener were added in appropriate amounts, respectively, and coated on a TAC (triacetyl cellulose) base to obtain a sample for sensitometry. These samples were exposed through an optical wedge and a filter at an exposure of 32 CMS and an exposure time of 1/100.
Exposure was performed under two conditions of 2 seconds and 8 seconds, and processing was performed according to the following processing steps.

Treatment process (treatment temperature 20 ° C.) Treatment time Current image 10 minutes Stop 2 minutes Fixing 5 minutes Water washing 10 minutes

[Developer] 2.5 m L-ascorbic acid 10.0 g Sodium metaborate tetrahydrate 35.0 g Potassium bromide 1.0 g Pure water 1000.0 ml [Stop solution] Acetic acid (3%) [ Fixer] Konica Fix (Konica Corporation)

The density of each developed sample was measured using an optical densitometer to determine the sensitivity. The sensitivity was obtained as the reciprocal of the exposure amount (true value) giving the density of the minimum optical density + 0.1. The evaluation results of each emulsion are shown in Table 2.

[0079]

[Table 2]

As is clear from Table 2, Em-1 of the present invention can be obtained by combining two or more polyvalent metal compounds.
In the silver halide emulsions of 2 to Em-20, not only the sensitivity is increased, but also the illuminance failure characteristic is good. In addition,
The combination of two or more polyvalent metal compounds used in the present invention may be a combination of compounds of different metal elements or a combination of compounds of the same metal element. When the compounds containing the same metal element are contained, a combination of a single salt and a complex, a complex having a different combination of ligands, a complex having a different central metal oxidation number, and the like are preferable. A combination of stereoisomers such as geometric isomers may be used. Further, it is preferable to combine compounds having different valences of metals, for example, Ir is preferable.

[0081]

According to the present invention, in a silver halide photographic emulsion containing a polyvalent metal compound, at least one of the metal compounds is uniformly distributed in the grains, and at least one of the other metal compounds is By local distribution inside the grain and / or on the grain surface, a silver halide photographic emulsion having improved sensitivity and illuminance failure characteristics can be obtained.

Claims (1)

[Claims] 1. A silver halide photographic emulsion comprising silver iodobromide grains or silver bromide grains containing two or more polyvalent metal compounds, at least one of which is uniformly distributed in the grains. And at least one of the other metal compounds
A silver halide photographic emulsion characterized in that the species are locally distributed inside and / or on the surface of the grain.